This is a competing renewal application for an NIMH-supported Clinical Research Center that is designed to enable clinical research to develop interventions for the treatment and prevention of the psychiatric disorders of late life in the context in which they most commonly occur in the presence of significant medical co-morbidity. The Specific Aims of the Center are: 1) To develop and conduct studies of the efficacy of treatments for the psychiatric disorders of late life in populations characterized by high levels of medical co-morbidity and disability; 2) To develop and validate methods for the recognition and diagnosis of depression and other psychiatric disorders in elderly patients, especially those with significant medical co-morbidity, both to enable the recognition of those individuals in "real life" clinical settings who would benefit from psychiatric treatments and to allow the identification of treatment-relevant sources of heterogeneity; 3. To identify consequences of depression and other psychiatric disorders of late life, to develop methods for evaluating the benefits of psychiatric treatment in domains that extend beyond the alleviation of symptoms, and to apply them in studies of treatment outcomes; 4) To provide formal and informal training opportunities and experiences in research in the areas of aging, mental disorders, and medical co-morbidity to enable students, residents, fellows, and junior faculty to develop as the next generation of productive researchers in this area; and, 5) To maintain mechanisms for the dissemination of knowledge derived from the research conducted in this Center and in the field as a whole to other researchers, health and mental health care professionals, and the public. The CRC consists of an Administrative Core, an Operational Core (that includes both an Assessment, Recruitment, and Tracking Service and Diagnostic Resources), a Biostatistics/Data Management Core, a Laboratory for the study of Behavioral Processes; and a Laboratory for Psychopharmacological/Biomedical Research; each of these components is described in a separate section of this proposal. In addition, the CRC includes an Educational Core that is funded through an NIMH/NRSA postdoctoral training grant.